Novel peptides with α-glucosidase inhibitory activity from Changii Radix hydrolysates.

[Display omitted] • Changii Radix protein contains α-glucosidase inhibitory peptides. Peptides released from in vitro simulated gastrointestinal digestion method manifested the best α-glucosidase inhibitory activity. • Peptides with smaller molecular weight and being more hydrophobic exerted the best hypoglycemic activity. • The GID-3-SG-2-RP-2 fraction exerted higher effect than the three synthesized peptides indicated peptide that acts synergistically or has greater activity. • Synthesized peptides KVIISAPSKDAPMF, SQHISTAGMEASGTSNMKF and STFQQMW showed α-glucosidase inhibitory activity with an with an IC 50 value of 32 μg/mL, 1.051 mg/mL and 1.104 mg/mL, respectively. • The results indicated that Changii Radix derived peptides may have potential functions in the prevention and management of type 2 diabetes. The objective of this research was to investigate the α-glucosidase inhibitory activity of peptides released from Changii Radix protein under the optimal enzymatic hydrolysis conditions of trypsin, flavourzyme, compound proteinase, papain, alkaline proteinase, neutral protease, and in vitro simulated human gastrointestinal digestive conditions. The hydrolysate with the best activity was further purified by ultrafiltration, size-exclusion chromatography and semi-preparative high performance liquid chromatography. The peptides in the most active fraction were subsequently identified by nano-LC–MS/MS and screened for bioactivity. As a result, the GID-3-SG-2-RP-2 fraction (with smaller molecular weight and more hydrophobic) manifested the highest effect with an IC 50 value of 32 μg/mL. Three peptides of this fraction were synthesized, SQHISTAGMEASGTSNMKF, KVIISAPSKDAPMF, and STFQQMW, and provided an IC 50 of 1.051, 0.032, and 1.104 mg/mL, respectively. Thus, the results indicated that Changii Radix derived peptides may have potential functions in the prevention and management of type 2 diabetes. [ABSTRACT FROM AUTHOR]